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Saturday, 28 April 2012

For many years Bristol has had on show one of the world’s smallest tortoises, the Egyptian or Kleineman’s Tortoise Testudo kleinemanni. Despite its’ name, sadly it is no longer found in Egypt itself, and is classed as Critically Endangered in the wild.

Threats to tortoises I have described in previous posts have mainly been from habitat destruction and collection for food. With T.kleinemanni the situation is different, as practically the entire cause of its current dire situation is collection for the pet trade.

Friday, 20 April 2012

A new addition to Bristol Zoos’ collection of turtles this year is a pair of one of the largest freshwater turtles in the world, the Giant Pond Terrapin Orlitia borneensis. With a shell length of 80cm and a maximum weight of 50kg (or as much as Cheryl Cole as the sign somewhat ungallantly puts it) this species is an impressive sight. As you might guess from the specific name, it is found in Borneo, but its range extends through Sumatra and through peninsula Malaya as well.

Friday, 13 April 2012

The aquatic chelonians I have been discussing so far all belong to a single family, the Geoemydidae. This is the most diverse of all living groups of turtles, with over 70 different species in 23 genera. The centre of distribution of the family is in south east Asia, with outliers in Europe and North Africa (the European Mauremys species), and a separate group in Central and South America (the Neotropical Wood Turtles Rhinoclemmys). Almost all of them are highly aquatic, and even the more terrestrial forms tend to prefer damp habitats. Despite this, they are generally believed to be close to the fully terrestrial tortoises such as the Aldabra Giant Tortoise and its smaller relatives. The age of the group is not clear, but it probably dates back to the late Cretaceous.

Friday, 6 April 2012

One of the peculiar features of the fauna and flora of Europe is that many of their closest relatives live in eastern Asia, with a vast gap in between with no connecting forms. This is a signal of the geological and climate events that have effected Eurasia, including the uplifting of the Himalaya following the collision of the Indian subcontinent with Asia, and above all the glaciations of the last few million years. In Europe the main mountain chains are aligned east-west, creating roadblocks to the migration of species north and south in response to climate change, whereas in eastern Asia mountain chains tend to be aligned north-south. As a result, while glaciations caused repeated extinctions in Europe, their Asian relatives managed to survive.